// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Machine check exception handling.
*
* Copyright 2013 IBM Corporation
* Author: Mahesh Salgaonkar <[email protected]>
*/
#undef DEBUG
#define pr_fmt(fmt) "mce: " fmt
#include <linux/hardirq.h>
#include <linux/types.h>
#include <linux/ptrace.h>
#include <linux/percpu.h>
#include <linux/export.h>
#include <linux/irq_work.h>
#include <linux/extable.h>
#include <linux/ftrace.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <asm/interrupt.h>
#include <asm/machdep.h>
#include <asm/mce.h>
#include <asm/nmi.h>
#include "setup.h"
static void machine_check_ue_event(struct machine_check_event *evt);
static void machine_process_ue_event(struct work_struct *work);
static DECLARE_WORK(mce_ue_event_work, machine_process_ue_event);
static BLOCKING_NOTIFIER_HEAD(mce_notifier_list);
int mce_register_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&mce_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(mce_register_notifier);
int mce_unregister_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&mce_notifier_list, nb);
}
EXPORT_SYMBOL_GPL(mce_unregister_notifier);
static void mce_set_error_info(struct machine_check_event *mce,
struct mce_error_info *mce_err)
{
mce->error_type = mce_err->error_type;
switch (mce_err->error_type) {
case MCE_ERROR_TYPE_UE:
mce->u.ue_error.ue_error_type = mce_err->u.ue_error_type;
break;
case MCE_ERROR_TYPE_SLB:
mce->u.slb_error.slb_error_type = mce_err->u.slb_error_type;
break;
case MCE_ERROR_TYPE_ERAT:
mce->u.erat_error.erat_error_type = mce_err->u.erat_error_type;
break;
case MCE_ERROR_TYPE_TLB:
mce->u.tlb_error.tlb_error_type = mce_err->u.tlb_error_type;
break;
case MCE_ERROR_TYPE_USER:
mce->u.user_error.user_error_type = mce_err->u.user_error_type;
break;
case MCE_ERROR_TYPE_RA:
mce->u.ra_error.ra_error_type = mce_err->u.ra_error_type;
break;
case MCE_ERROR_TYPE_LINK:
mce->u.link_error.link_error_type = mce_err->u.link_error_type;
break;
case MCE_ERROR_TYPE_UNKNOWN:
default:
break;
}
}
void mce_irq_work_queue(void)
{
/* Raise decrementer interrupt */
arch_irq_work_raise();
set_mce_pending_irq_work();
}
/*
* Decode and save high level MCE information into per cpu buffer which
* is an array of machine_check_event structure.
*/
void save_mce_event(struct pt_regs *regs, long handled,
struct mce_error_info *mce_err,
uint64_t nip, uint64_t addr, uint64_t phys_addr)
{
int index = local_paca->mce_info->mce_nest_count++;
struct machine_check_event *mce;
mce = &local_paca->mce_info->mce_event[index];
/*
* Return if we don't have enough space to log mce event.
* mce_nest_count may go beyond MAX_MC_EVT but that's ok,
* the check below will stop buffer overrun.
*/
if (index >= MAX_MC_EVT)
return;
/* Populate generic machine check info */
mce->version = MCE_V1;
mce->srr0 = nip;
mce->srr1 = regs->msr;
mce->gpr3 = regs->gpr[3];
mce->in_use = 1;
mce->cpu = get_paca()->paca_index;
/* Mark it recovered if we have handled it and MSR(RI=1). */
if (handled && (regs->msr & MSR_RI))
mce->disposition = MCE_DISPOSITION_RECOVERED;
else
mce->disposition = MCE_DISPOSITION_NOT_RECOVERED;
mce->initiator = mce_err->initiator;
mce->severity = mce_err->severity;
mce->sync_error = mce_err->sync_error;
mce->error_class = mce_err->error_class;
/*
* Populate the mce error_type and type-specific error_type.
*/
mce_set_error_info(mce, mce_err);
if (mce->error_type == MCE_ERROR_TYPE_UE)
mce->u.ue_error.ignore_event = mce_err->ignore_event;
/*
* Raise irq work, So that we don't miss to log the error for
* unrecoverable errors.
*/
if (mce->disposition == MCE_DISPOSITION_NOT_RECOVERED)
mce_irq_work_queue();
if (!addr)
return;
if (mce->error_type == MCE_ERROR_TYPE_TLB) {
mce->u.tlb_error.effective_address_provided = true;
mce->u.tlb_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_SLB) {
mce->u.slb_error.effective_address_provided = true;
mce->u.slb_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_ERAT) {
mce->u.erat_error.effective_address_provided = true;
mce->u.erat_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_USER) {
mce->u.user_error.effective_address_provided = true;
mce->u.user_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_RA) {
mce->u.ra_error.effective_address_provided = true;
mce->u.ra_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_LINK) {
mce->u.link_error.effective_address_provided = true;
mce->u.link_error.effective_address = addr;
} else if (mce->error_type == MCE_ERROR_TYPE_UE) {
mce->u.ue_error.effective_address_provided = true;
mce->u.ue_error.effective_address = addr;
if (phys_addr != ULONG_MAX) {
mce->u.ue_error.physical_address_provided = true;
mce->u.ue_error.physical_address = phys_addr;
machine_check_ue_event(mce);
}
}
return;
}
/*
* get_mce_event:
* mce Pointer to machine_check_event structure to be filled.
* release Flag to indicate whether to free the event slot or not.
* 0 <= do not release the mce event. Caller will invoke
* release_mce_event() once event has been consumed.
* 1 <= release the slot.
*
* return 1 = success
* 0 = failure
*
* get_mce_event() will be called by platform specific machine check
* handle routine and in KVM.
* When we call get_mce_event(), we are still in interrupt context and
* preemption will not be scheduled until ret_from_expect() routine
* is called.
*/
int get_mce_event(struct machine_check_event *mce, bool release)
{
int index = local_paca->mce_info->mce_nest_count - 1;
struct machine_check_event *mc_evt;
int ret = 0;
/* Sanity check */
if (index < 0)
return ret;
/* Check if we have MCE info to process. */
if (index < MAX_MC_EVT) {
mc_evt = &local_paca->mce_info->mce_event[index];
/* Copy the event structure and release the original */
if (mce)
*mce = *mc_evt;
if (release)
mc_evt->in_use = 0;
ret = 1;
}
/* Decrement the count to free the slot. */
if (release)
local_paca->mce_info->mce_nest_count--;
return ret;
}
void release_mce_event(void)
{
get_mce_event(NULL, true);
}
static void machine_check_ue_work(void)
{
schedule_work(&mce_ue_event_work);
}
/*
* Queue up the MCE event which then can be handled later.
*/
static void machine_check_ue_event(struct machine_check_event *evt)
{
int index;
index = local_paca->mce_info->mce_ue_count++;
/* If queue is full, just return for now. */
if (index >= MAX_MC_EVT) {
local_paca->mce_info->mce_ue_count--;
return;
}
memcpy(&local_paca->mce_info->mce_ue_event_queue[index],
evt, sizeof(*evt));
}
/*
* Queue up the MCE event which then can be handled later.
*/
void machine_check_queue_event(void)
{
int index;
struct machine_check_event evt;
if (!get_mce_event(&evt, MCE_EVENT_RELEASE))
return;
index = local_paca->mce_info->mce_queue_count++;
/* If queue is full, just return for now. */
if (index >= MAX_MC_EVT) {
local_paca->mce_info->mce_queue_count--;
return;
}
memcpy(&local_paca->mce_info->mce_event_queue[index],
&evt, sizeof(evt));
mce_irq_work_queue();
}
void mce_common_process_ue(struct pt_regs *regs,
struct mce_error_info *mce_err)
{
const struct exception_table_entry *entry;
entry = search_kernel_exception_table(regs->nip);
if (entry) {
mce_err->ignore_event = true;
regs_set_return_ip(regs, extable_fixup(entry));
}
}
/*
* process pending MCE event from the mce event queue. This function will be
* called during syscall exit.
*/
static void machine_process_ue_event(struct work_struct *work)
{
int index;
struct machine_check_event *evt;
while (local_paca->mce_info->mce_ue_count > 0) {
index = local_paca->mce_info->mce_ue_count - 1;
evt = &local_paca->mce_info->mce_ue_event_queue[index];
blocking_notifier_call_chain(&mce_notifier_list, 0, evt);
#ifdef CONFIG_MEMORY_FAILURE
/*
* This should probably queued elsewhere, but
* oh! well
*
* Don't report this machine check because the caller has a
* asked us to ignore the event, it has a fixup handler which
* will do the appropriate error handling and reporting.
*/
if (evt->error_type == MCE_ERROR_TYPE_UE) {
if (evt->u.ue_error.ignore_event) {
local_paca->mce_info->mce_ue_count--;
continue;
}
if (evt->u.ue_error.physical_address_provided) {
unsigned long pfn;
pfn = evt->u.ue_error.physical_address >>
PAGE_SHIFT;
memory_failure(pfn, 0);
} else
pr_warn("Failed to identify bad address from "
"where the uncorrectable error (UE) "
"was generated\n");
}
#endif
local_paca->mce_info->mce_ue_count--;
}
}
/*
* process pending MCE event from the mce event queue. This function will be
* called during syscall exit.
*/
static void machine_check_process_queued_event(void)
{
int index;
struct machine_check_event *evt;
add_taint(TAINT_MACHINE_CHECK, LOCKDEP_NOW_UNRELIABLE);
/*
* For now just print it to console.
* TODO: log this error event to FSP or nvram.
*/
while (local_paca->mce_info->mce_queue_count > 0) {
index = local_paca->mce_info->mce_queue_count - 1;
evt = &local_paca->mce_info->mce_event_queue[index];
if (evt->error_type == MCE_ERROR_TYPE_UE &&
evt->u.ue_error.ignore_event) {
local_paca->mce_info->mce_queue_count--;
continue;
}
machine_check_print_event_info(evt, false, false);
local_paca->mce_info->mce_queue_count--;
}
}
void set_mce_pending_irq_work(void)
{
local_paca->mce_pending_irq_work = 1;
}
void clear_mce_pending_irq_work(void)
{
local_paca->mce_pending_irq_work = 0;
}
void mce_run_irq_context_handlers(void)
{
if (unlikely(local_paca->mce_pending_irq_work)) {
if (ppc_md.machine_check_log_err)
ppc_md.machine_check_log_err();
machine_check_process_queued_event();
machine_check_ue_work();
clear_mce_pending_irq_work();
}
}
void machine_check_print_event_info(struct machine_check_event *evt,
bool user_mode, bool in_guest)
{
const char *level, *sevstr, *subtype, *err_type, *initiator;
uint64_t ea = 0, pa = 0;
int n = 0;
char dar_str[50];
char pa_str[50];
static const char *mc_ue_types[] = {
"Indeterminate",
"Instruction fetch",
"Page table walk ifetch",
"Load/Store",
"Page table walk Load/Store",
};
static const char *mc_slb_types[] = {
"Indeterminate",
"Parity",
"Multihit",
};
static const char *mc_erat_types[] = {
"Indeterminate",
"Parity",
"Multihit",
};
static const char *mc_tlb_types[] = {
"Indeterminate",
"Parity",
"Multihit",
};
static const char *mc_user_types[] = {
"Indeterminate",
"tlbie(l) invalid",
"scv invalid",
};
static const char *mc_ra_types[] = {
"Indeterminate",
"Instruction fetch (bad)",
"Instruction fetch (foreign/control memory)",
"Page table walk ifetch (bad)",
"Page table walk ifetch (foreign/control memory)",
"Load (bad)",
"Store (bad)",
"Page table walk Load/Store (bad)",
"Page table walk Load/Store (foreign/control memory)",
"Load/Store (foreign/control memory)",
};
static const char *mc_link_types[] = {
"Indeterminate",
"Instruction fetch (timeout)",
"Page table walk ifetch (timeout)",
"Load (timeout)",
"Store (timeout)",
"Page table walk Load/Store (timeout)",
};
static const char *mc_error_class[] = {
"Unknown",
"Hardware error",
"Probable Hardware error (some chance of software cause)",
"Software error",
"Probable Software error (some chance of hardware cause)",
};
/* Print things out */
if (evt->version != MCE_V1) {
pr_err("Machine Check Exception, Unknown event version %d !\n",
evt->version);
return;
}
switch (evt->severity) {
case MCE_SEV_NO_ERROR:
level = KERN_INFO;
sevstr = "Harmless";
break;
case MCE_SEV_WARNING:
level = KERN_WARNING;
sevstr = "Warning";
break;
case MCE_SEV_SEVERE:
level = KERN_ERR;
sevstr = "Severe";
break;
case MCE_SEV_FATAL:
default:
level = KERN_ERR;
sevstr = "Fatal";
break;
}
switch(evt->initiator) {
case MCE_INITIATOR_CPU:
initiator = "CPU";
break;
case MCE_INITIATOR_PCI:
initiator = "PCI";
break;
case MCE_INITIATOR_ISA:
initiator = "ISA";
break;
case MCE_INITIATOR_MEMORY:
initiator = "Memory";
break;
case MCE_INITIATOR_POWERMGM:
initiator = "Power Management";
break;
case MCE_INITIATOR_UNKNOWN:
default:
initiator = "Unknown";
break;
}
switch (evt->error_type) {
case MCE_ERROR_TYPE_UE:
err_type = "UE";
subtype = evt->u.ue_error.ue_error_type <
ARRAY_SIZE(mc_ue_types) ?
mc_ue_types[evt->u.ue_error.ue_error_type]
: "Unknown";
if (evt->u.ue_error.effective_address_provided)
ea = evt->u.ue_error.effective_address;
if (evt->u.ue_error.physical_address_provided)
pa = evt->u.ue_error.physical_address;
break;
case MCE_ERROR_TYPE_SLB:
err_type = "SLB";
subtype = evt->u.slb_error.slb_error_type <
ARRAY_SIZE(mc_slb_types) ?
mc_slb_types[evt->u.slb_error.slb_error_type]
: "Unknown";
if (evt->u.slb_error.effective_address_provided)
ea = evt->u.slb_error.effective_address;
break;
case MCE_ERROR_TYPE_ERAT:
err_type = "ERAT";
subtype = evt->u.erat_error.erat_error_type <
ARRAY_SIZE(mc_erat_types) ?
mc_erat_types[evt->u.erat_error.erat_error_type]
: "Unknown";
if (evt->u.erat_error.effective_address_provided)
ea = evt->u.erat_error.effective_address;
break;
case MCE_ERROR_TYPE_TLB:
err_type = "TLB";
subtype = evt->u.tlb_error.tlb_error_type <
ARRAY_SIZE(mc_tlb_types) ?
mc_tlb_types[evt->u.tlb_error.tlb_error_type]
: "Unknown";
if (evt->u.tlb_error.effective_address_provided)
ea = evt->u.tlb_error.effective_address;
break;
case MCE_ERROR_TYPE_USER:
err_type = "User";
subtype = evt->u.user_error.user_error_type <
ARRAY_SIZE(mc_user_types) ?
mc_user_types[evt->u.user_error.user_error_type]
: "Unknown";
if (evt->u.user_error.effective_address_provided)
ea = evt->u.user_error.effective_address;
break;
case MCE_ERROR_TYPE_RA:
err_type = "Real address";
subtype = evt->u.ra_error.ra_error_type <
ARRAY_SIZE(mc_ra_types) ?
mc_ra_types[evt->u.ra_error.ra_error_type]
: "Unknown";
if (evt->u.ra_error.effective_address_provided)
ea = evt->u.ra_error.effective_address;
break;
case MCE_ERROR_TYPE_LINK:
err_type = "Link";
subtype = evt->u.link_error.link_error_type <
ARRAY_SIZE(mc_link_types) ?
mc_link_types[evt->u.link_error.link_error_type]
: "Unknown";
if (evt->u.link_error.effective_address_provided)
ea = evt->u.link_error.effective_address;
break;
case MCE_ERROR_TYPE_DCACHE:
err_type = "D-Cache";
subtype = "Unknown";
break;
case MCE_ERROR_TYPE_ICACHE:
err_type = "I-Cache";
subtype = "Unknown";
break;
default:
case MCE_ERROR_TYPE_UNKNOWN:
err_type = "Unknown";
subtype = "";
break;
}
dar_str[0] = pa_str[0] = '\0';
if (ea && evt->srr0 != ea) {
/* Load/Store address */
n = sprintf(dar_str, "DAR: %016llx ", ea);
if (pa)
sprintf(dar_str + n, "paddr: %016llx ", pa);
} else if (pa) {
sprintf(pa_str, " paddr: %016llx", pa);
}
printk("%sMCE: CPU%d: machine check (%s) %s %s %s %s[%s]\n",
level, evt->cpu, sevstr, in_guest ? "Guest" : "",
err_type, subtype, dar_str,
evt->disposition == MCE_DISPOSITION_RECOVERED ?
"Recovered" : "Not recovered");
if (in_guest || user_mode) {
printk("%sMCE: CPU%d: PID: %d Comm: %s %sNIP: [%016llx]%s\n",
level, evt->cpu, current->pid, current->comm,
in_guest ? "Guest " : "", evt->srr0, pa_str);
} else {
printk("%sMCE: CPU%d: NIP: [%016llx] %pS%s\n",
level, evt->cpu, evt->srr0, (void *)evt->srr0, pa_str);
}
printk("%sMCE: CPU%d: Initiator %s\n", level, evt->cpu, initiator);
subtype = evt->error_class < ARRAY_SIZE(mc_error_class) ?
mc_error_class[evt->error_class] : "Unknown";
printk("%sMCE: CPU%d: %s\n", level, evt->cpu, subtype);
#ifdef CONFIG_PPC_64S_HASH_MMU
/* Display faulty slb contents for SLB errors. */
if (evt->error_type == MCE_ERROR_TYPE_SLB && !in_guest)
slb_dump_contents(local_paca->mce_faulty_slbs);
#endif
}
EXPORT_SYMBOL_GPL(machine_check_print_event_info);
/*
* This function is called in real mode. Strictly no printk's please.
*
* regs->nip and regs->msr contains srr0 and ssr1.
*/
DEFINE_INTERRUPT_HANDLER_NMI(machine_check_early)
{
long handled = 0;
hv_nmi_check_nonrecoverable(regs);
/*
* See if platform is capable of handling machine check.
*/
if (ppc_md.machine_check_early)
handled = ppc_md.machine_check_early(regs);
return handled;
}
/* Possible meanings for HMER_DEBUG_TRIG bit being set on POWER9 */
static enum {
DTRIG_UNKNOWN,
DTRIG_VECTOR_CI, /* need to emulate vector CI load instr */
DTRIG_SUSPEND_ESCAPE, /* need to escape from TM suspend mode */
} hmer_debug_trig_function;
static int init_debug_trig_function(void)
{
int pvr;
struct device_node *cpun;
struct property *prop = NULL;
const char *str;
/* First look in the device tree */
preempt_disable();
cpun = of_get_cpu_node(smp_processor_id(), NULL);
if (cpun) {
of_property_for_each_string(cpun, "ibm,hmi-special-triggers",
prop, str) {
if (strcmp(str, "bit17-vector-ci-load") == 0)
hmer_debug_trig_function = DTRIG_VECTOR_CI;
else if (strcmp(str, "bit17-tm-suspend-escape") == 0)
hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
}
of_node_put(cpun);
}
preempt_enable();
/* If we found the property, don't look at PVR */
if (prop)
goto out;
pvr = mfspr(SPRN_PVR);
/* Check for POWER9 Nimbus (scale-out) */
if ((PVR_VER(pvr) == PVR_POWER9) && (pvr & 0xe000) == 0) {
/* DD2.2 and later */
if ((pvr & 0xfff) >= 0x202)
hmer_debug_trig_function = DTRIG_SUSPEND_ESCAPE;
/* DD2.0 and DD2.1 - used for vector CI load emulation */
else if ((pvr & 0xfff) >= 0x200)
hmer_debug_trig_function = DTRIG_VECTOR_CI;
}
out:
switch (hmer_debug_trig_function) {
case DTRIG_VECTOR_CI:
pr_debug("HMI debug trigger used for vector CI load\n");
break;
case DTRIG_SUSPEND_ESCAPE:
pr_debug("HMI debug trigger used for TM suspend escape\n");
break;
default:
break;
}
return 0;
}
__initcall(init_debug_trig_function);
/*
* Handle HMIs that occur as a result of a debug trigger.
* Return values:
* -1 means this is not a HMI cause that we know about
* 0 means no further handling is required
* 1 means further handling is required
*/
long hmi_handle_debugtrig(struct pt_regs *regs)
{
unsigned long hmer = mfspr(SPRN_HMER);
long ret = 0;
/* HMER_DEBUG_TRIG bit is used for various workarounds on P9 */
if (!((hmer & HMER_DEBUG_TRIG)
&& hmer_debug_trig_function != DTRIG_UNKNOWN))
return -1;
hmer &= ~HMER_DEBUG_TRIG;
/* HMER is a write-AND register */
mtspr(SPRN_HMER, ~HMER_DEBUG_TRIG);
switch (hmer_debug_trig_function) {
case DTRIG_VECTOR_CI:
/*
* Now to avoid problems with soft-disable we
* only do the emulation if we are coming from
* host user space
*/
if (regs && user_mode(regs))
ret = local_paca->hmi_p9_special_emu = 1;
break;
default:
break;
}
/*
* See if any other HMI causes remain to be handled
*/
if (hmer & mfspr(SPRN_HMEER))
return -1;
return ret;
}
/*
* Return values:
*/
DEFINE_INTERRUPT_HANDLER_NMI(hmi_exception_realmode)
{
int ret;
local_paca->hmi_irqs++;
ret = hmi_handle_debugtrig(regs);
if (ret >= 0)
return ret;
wait_for_subcore_guest_exit();
if (ppc_md.hmi_exception_early)
ppc_md.hmi_exception_early(regs);
wait_for_tb_resync();
return 1;
}
void __init mce_init(void)
{
struct mce_info *mce_info;
u64 limit;
int i;
limit = min(ppc64_bolted_size(), ppc64_rma_size);
for_each_possible_cpu(i) {
mce_info = memblock_alloc_try_nid(sizeof(*mce_info),
__alignof__(*mce_info),
MEMBLOCK_LOW_LIMIT,
limit, early_cpu_to_node(i));
if (!mce_info)
goto err;
paca_ptrs[i]->mce_info = mce_info;
}
return;
err:
panic("Failed to allocate memory for MCE event data\n");
}
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